1. Field of the Invention
The present invention relates generally to boring bars that are mounted to machine tools and are used for boring internal surfaces in work pieces that are typically rotated by a machine tool. More particularly the present invention pertains to boring bars having an internal coolant supply to discharge a liquid coolant and cutting fluid medium immediately at the site of metal cutting by a metal cutting insert of a boring bar. Even more specifically, a clamp releasably securing a metal cutting insert to the cutter support head of a boring bar defines a coolant flow passage having an exit or discharge opening directed immediately at the site of metal cutting by the insert maintains the metal cutting insert as cool as possible during boring operations and thereby minimizes heat induced wear and deterioration and thus enhances the service life of the metal cutting insert.
2. Description of the Prior Art
During metal cutting operations, especially when heavy cuts of metal are taken during rough metal cutting, it is typical for the metal cutting machine to be provided with a coolant fluid conduit through which a coolant and metal cutting fluid medium is pumped to the site of metal cutting. Typically, a fluid supply conduit, such as a flexible coolant supply hose in communication with the discharge of a coolant supply pump, is provided which can be selectively oriented for delivery of the flowing coolant fluid medium to the cutter insert of the machine tool. The continuous supply of coolant fluid to the metal cutting site minimizes heat build-up at the metal cutting site and thus maintains lower working or cutting temperature of the metal cutting element and ensures its extended service life.
When metal cutting operations are carried out internally of a rotating workpiece, such as is the case when boring operations are being carried out, the boring bar being used can have considerable length, thus making it difficult to efficiently support a coolant supply tube or hose and conduct an adequate supply of coolant fluid to the immediate region of the metal cutting insert of the boring bar. It is desirable, therefore, to provide a metal boring tool system that does not require a coolant supply conduit to be supported along the length of a boring bar and which ensures efficient and adequate delivery of coolant fluid to the immediate site of metal cutting for maintaining the cutting tool and the metal being cut within a predetermined temperature range.